Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 4, NWS San Francisco Bay Area, CA

November 30, 2012Monterey County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Nov 30, 2012, 10:38 AM PST for Monterey County, California. It was in force for 82 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Nov 30, 2012, 10:38 AM PST (18:38 UTC)
Expired: Nov 30, 2012, 12:00 PM PST
In force: 82 min
Issued by: NWS San Francisco Bay Area, CA
Area: Storm-based polygon
Flood severity: None

County Monterey County, CA

The radar

The San Francisco radar (KMUX), 111 km from the middle of the area, began a volume at 18:37 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Nov 30, 11:59 AM PST	FLASH FLOOD	6 Nw Pico Blanco Campgr, CA	SPOTTER REPORTS RAIN INTENSITY INCREASING AGAIN AND FLASH FLOODING CONTINUING TO IMPACT DRAINAGE CULVERTS.
Nov 30, 12:10 PM PST	HEAVY RAIN 8.03	5 Nnw Lucia, CA	8.03 INCHES MEASURED AT MINING RIDGE RAWS SITE AT 3288 FT ELEVATION. 3.42 INCHES HAVE FALLEN IN THE PAST 3 HOURS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 6.6 hours before the alert went out and 179 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 60 J/kg
Mixed-layer CIN: -60 J/kg
Mixed-layer LCL: 551 m above ground
0-6 km bulk shear: 67 kt
0-1 km storm-relative helicity: 462 m²/s²
0-3 km storm-relative helicity: 616 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

844 
WGUS56 KMTR 301838
FFWMTR
CAC053-302000-
/O.NEW.KMTR.FF.W.0004.121130T1838Z-121130T2000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1038 AM PST FRI NOV 30 2012

THE NATIONAL WEATHER SERVICE IN THE SAN FRANCISCO BAY AREA HAS
ISSUED A

* FLASH FLOOD WARNING FOR...
  MONTEREY COUNTY IN WESTERN CALIFORNIA...
  THIS INCLUDES THE CITIES OF...TASSAJARA HOT SPRINGS...JAMESBURG...
  BIG SUR VILLAGE...

* UNTIL NOON PST.

* AT 1036 AM PST...NWS DOPPLER RADAR AND AUTOMATED RAIN GAGES IN THE 
HIGH TERRAIN OF MONTEREY COUNTY INDICATED THAT STORM TOTAL RAINS OF 
4 TO 6 INCHES HAVE ALREADY FALLEN IN THE AREA. HOURLY RATES OF UP TO 
1 INCH PER HOUR WILL CONTINUE. SPOTTERS IN THE AREA REPORT FLASH 
FLOODING AND EROSION IS TAKING PLACE DUE TO EXCESSIVE RAINFALL. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PICO BLANCO
  CAMPGROUND AND ANDREW MOLERA STATE PARK

A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT.

RUNOFF FROM HEAVY RAINFALL WILL CAUSE LOCALIZED FLOODING OF SMALL
CREEKS AND STREAMS AS WELL AS ROADWAYS...UNDERPASSES AND OTHER LOW
LYING SPOTS. DO NOT ATTEMPT TO CROSS SWIFTLY FLOWING WATER OR WATER
OF UNKNOWN DEPTH. TURN AROUND...DONT DROWN.

IT IS IMPORTANT FOR CAMPERS AND HIKERS TO KNOW WHERE THEY ARE
RELATIVE TO CREEKS...STREAMS...OR RIVERS WHICH CAN BECOME DANGEROUS
IN HEAVY RAINS. BE PARTICULARLY AWARE IN HILLY TERRAIN WHERE MANY LOW
WATER CROSSINGS CAN QUICKLY BECOME KILLERS.

IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE UP TO HIGHER GROUND 
TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING 
WHEN WATER BEGINS RISING.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE.

LAT...LON 3601 12158 3614 12167 3620 12175 3623 12182
      3632 12191 3636 12192 3648 12184 3629 12155
      3603 12138 3602 12151 3601 12151

$$

JOHNSON

The office that day

Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Nov 30, 4:16 AM PST	Flash Flood Warning	MTR	Sonoma	119 min
Nov 30, 5:38 AM PST	Areal Flood Advisory	MTR	Santa Cruz	6 hr
Nov 30, 6:22 AM PST	Flash Flood Warning	MTR	Sonoma	3 hr
Nov 30, 8:27 AM PST	Areal Flood Advisory	MTR	Alameda, Contra Costa, Marin, Monterey, San Benito, City and County of San Francisco and 3 more	3 hr
Nov 30, 9:02 AM PST	Areal Flood Advisory	MTR	Marin, Napa, Sonoma	118 min
Nov 30, 9:29 AM PST	Flash Flood Warning	MTR	Monterey	61 min
Nov 30, 11:03 AM PST	River Flood Watch	MTR	Sonoma	26 days
Nov 30, 11:25 AM PST	Areal Flood Advisory	MTR	Alameda, Contra Costa, Marin, Monterey, San Benito, City and County of San Francisco and 3 more	3 hr
Nov 30, 11:59 AM PST	Flash Flood Warning	MTR	Monterey	3 hr
Nov 30, 2:56 PM PST	Small Craft Advisory	MTR		47 hr

Nearby

Flash Flood Warnings in California, 2012 Every flash flood warning in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.